Oil cooling arrangement and method of cooling oil

ABSTRACT

An oil cooling arrangement includes a first manifold and a second manifold, each configured to route an oil. Further included is a first tube having a first end proximate the first manifold and a second end proximate the second manifold, wherein the first tube is configured to receive the oil and route the oil toward the second manifold. Yet further included is a second tube having a third end proximate the second manifold and a fourth end proximate the first manifold, wherein the second tube is configured to route the oil from the second manifold toward the first manifold. Also included is a turbine exhaust path configured to route an exhaust flow, wherein the first tube and the second tube are disposed along the turbine exhaust path, wherein the oil is cooled upon passage of the exhaust flow over the first tube and the second tube.

This invention was made with Government support under contract NNM07AB03C awarded by NASA. The Government has certain rights in the invention.

BACKGROUND OF THE INVENTION

The present invention relates to aerospace systems, and more particularly to an oil cooling arrangement for an aerospace system, as well as a method of cooling oil.

A large number of applications require cooling of various system fluids, such as oil, for example. One application relates to a space launch vehicle that requires a power source for an engine thrust vector control system. Currently, the power source utilizes a hot gas, such as hydrazine, to drive a turbine that provides mechanical rotating power to a hydraulic pump, generator or other power conversion device. Transmission of this power typically results in heat generation within the power device due to mechanical efficiency losses. In applications having operating durations exceeding several minutes or hours, heat generation must be managed to avoid system failure. Efforts to effectively manage the heat generation are complicated by the requirement that the power device must operate in a space vacuum operating environment. One prior effort to manage the heat included utilizing an external water spray boiler to achieve heat dissipation, but a specialized heat exchanger, controller and an on-board source of water are all required. Such a complicated system inherently imposes several undesirable effects, including additional weight and reduced efficiency of the overall system.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment, an oil cooling arrangement includes a first manifold. Also included is a second manifold, wherein the first manifold and the second manifold are each configured to route an oil. Further included is a first tube having a first end proximate the first manifold and a second end proximate the second manifold, wherein the first tube is configured to receive the oil and route the oil toward the second manifold. Yet further included is a second tube having a third end proximate the second manifold and a fourth end proximate the first manifold, wherein the second tube is configured to route the oil from the second manifold toward the first manifold. Also included is a turbine exhaust path configured to route an exhaust flow, wherein the first tube and the second tube are disposed along the turbine exhaust path, wherein the oil is cooled upon passage of the exhaust flow over the first tube and the second tube.

According to another embodiment, a method of cooling oil is provided. The method includes supplying an oil to a first manifold of an oil cooling arrangement. The method also includes routing the oil through a first tube from the first manifold to a second manifold, wherein the first tube is disposed in a turbine exhaust path. The method further includes routing the oil through a second tube from the second manifold to the first manifold, wherein the second tube is disposed in the turbine exhaust path. The method yet further includes flowing an exhaust flow through the turbine exhaust path and over the first tube and the second tube for cooling the oil routed therein.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of an oil cooling arrangement;

FIG. 2 is a perspective view of a cover member of the oil cooling arrangement;

FIG. 3 is a side, elevational, cross-sectional view of the oil cooling arrangement;

FIG. 4 is a side elevational view of the oil cooling arrangement; and

FIG. 5 is a flow diagram illustrating a method of cooling oil.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an oil cooling arrangement 10 is generally shown. The oil cooling arrangement 10 is in fluid communication with a system requiring an oil 12. The oil cooling arrangement 10 is configured to manage the temperature of the oil 12 that is commonly heated due to heat dissipation associated with operation of the system. The oil cooling arrangement 10 is operatively coupled to a power device, such as a turbine system 14 that provides mechanical rotating power to a hydraulic pump, generator or other power conversion device. The oil cooling arrangement 10 and the turbine system 14 may be integrated with various applications, but in one embodiment the oil cooling arrangement 10 and the turbine system 14 are employed in conjunction with an aerospace application. More particularly, it is contemplated that a space launch vehicle operating in vacuum in space may benefit from the oil cooling arrangement 10 described herein.

The turbine system 14 includes at least one turbine nozzle 16 configured to distribute a propellant fuel 18 to the turbine system 14. In an exemplary embodiment, the propellant fuel 18 is a cold gas, such as helium or hydrogen gas, for example. Irrespective of the precise fuel employed, the propellant fuel 18 drives a turbine wheel 20 and the mechanical power is converted to a desired power type. Subsequent to passing over and driving the turbine wheel 20, the propellant fuel 18, and any air mixed therewith, is routed through an exhaust housing 22 as an exhaust flow 24. The interior region defined by the exhaust housing 22 is referred to as a turbine exhaust path 26. The illustrated embodiment is shown with a shipping port cover 28 proximate an exhaust outlet 30. By employing the cold gas in the space vacuum environment, the exhaust flow 24 passing through the turbine exhaust path 26 is cold, relative to temperatures of operating environments for adjacent components and systems, such as a component or system employing the oil 12 described above. In one embodiment, the temperature of the exhaust flow 24 ranges from about −100° F. (about −73° C.) to about −200° F. (about −129° C.).

The oil cooling arrangement 10 is operatively coupled at a plurality of locations with the turbine system 14. Specifically, the oil cooling arrangement 10 is at least partially disposed within the turbine exhaust path 26 and coupled at an interior location of the exhaust housing 22. Additionally, as illustrated, the oil cooling arrangement 10 is coupled to an exterior surface 32 of the exhaust housing 22, such as with a plurality of mechanical fasteners 34. The oil cooling arrangement 10 comprises a plurality of tubes 36 predominantly or fully disposed within the exhaust housing 22 along the turbine exhaust path 26. In one embodiment, the plurality of tubes 36 comprises a first tube 38, a second tube 40, a third tube 42 and a fourth tube 44. Each of the plurality of tubes 36 extends between and is fluidly coupled with a first manifold 46 and a second manifold 48 at respective ends of each of the plurality of tubes 36. The first manifold 46 is operatively coupled to the exhaust housing 22 and is disposed proximate the exhaust housing 22. In the exemplary embodiment, the first manifold 46 is disposed partially or fully at an exterior region to the turbine exhaust path 26. Integrally formed with, or operatively coupled to, the first manifold 46 is a cover member 50 that includes an inlet 52 and an outlet 54 for receiving and expelling the oil 12 relative to the oil cooling arrangement 10. The second manifold 48 is disposed fully within the turbine exhaust path 26 and is operatively coupled to the turbine system 14 therein.

Referring now to FIG. 2, the cover member 50 is illustrated in greater detail with a portion cutaway for clarity. As noted above, the cover member 50 is integrally formed with, or operatively coupled to, the first manifold 46. The oil 12 is initially received by the oil cooling arrangement 10 via the inlet 52 from a supply (not illustrated). The inlet 52 is fluidly coupled to the first manifold 46, which is configured to route the oil 12 to at least one, but typically a plurality of tubes configured to route the oil 12 from the first manifold 46 to the second manifold 48. In the exemplary embodiment, the oil 12 is split and routed to the first tube 38 and the third tube 42. The inlet 52 is also fluidly coupled to the outlet 54 by an oil cooling arrangement bypass 56 configured to divert the oil 12 from routing through the plurality of tubes 36 of the oil cooling arrangement 10. Diversion of the oil 12 is selectively controlled with a thermal control valve 58 that is moveable between a first position and a second position. The first position corresponds to a fully open position that opens the oil cooling arrangement bypass 56, thereby causing the oil 12 to be diverted to the outlet 54. Bypassing the oil cooling arrangement 10 is desirable at operating temperatures that do not require cooling of the oil 12. In one embodiment, the thermal control valve 58 is in the fully open position at temperatures less than and equal to about 250° F. (about 121° C.). As the temperature of the operating environment begins to rise, thereby requiring cooling of the oil 12, the thermal control valve 58 transitions toward the second position. The second position corresponds to a fully closed position that closes the oil cooling arrangement bypass 56, thereby causing the oil 12 to be routed to the plurality of tubes 36 of the oil cooling arrangement 10. In one embodiment, the thermal control valve 58 is in the fully closed position at temperatures greater than and equal to about 270° F. (about 132° C.).

Integrally formed with the thermal control valve 58 is a pressure relief valve 60 that detects a pressure within passages of the oil cooling arrangement 10. The pressure relief valve 60 is configured to alter the cross-sectional area of one or more passages proximate the inlet 52 and/or outlet 54, thereby increasing the volumetric flow rate of the oil 12 in the event of a partial blockage due to oil clotting or the like. In one embodiment, the pressure relief valve 60 initiates relief at about pressure differential of about 25 psid (about 172 kPa differential).

Referring now to FIGS. 3 and 4, the oil cooling arrangement 10 is shown in greater detail. As indicated by the arrows representing the direction of flow of the oil 12, it can be appreciated that the second tube 40 and the fourth tube 44 are shown from the illustrated side, while the first tube 38 and the third tube 42 are hidden from view. Similarly, the outlet 54 is illustrated, while the inlet 52 is hidden. As described in detail above, the inlet 52 routes the oil to the first manifold 46 for splitting of the oil 12 into the first tube 38 and the third tube 42. Upon reaching the second manifold 48, the oil 12 is directed to the second tube 40 and the fourth tube 44. Specifically, the second manifold 48 includes a first fluid path 62 fluidly coupling the first tube 38 and the second tube 40, as well as a second fluid path 64 fluidly coupling the third tube 42 and the fourth tube 44. Within the second tube 40 and the fourth tube 44, the oil 12 is routed from the second manifold 48 toward the first manifold 46 and is subsequently expelled via the outlet 54.

While flowing through the plurality of tubes 36, which are disposed within the turbine exhaust path 26, the oil 12 is cooled due to heat transfer associated with the exhaust flow 24 passing over an outer surface 68 of the plurality of tubes 36. As described above, the exhaust flow 24 is relatively cold and is therefore suitable for cooling of the oil 12 flowing within the plurality of tubes 36. To enhance the heat transfer to the plurality of tubes 36 from the exhaust flow 24, a plurality of fins 70 extend outwardly from the outer surface 68 of the plurality of tubes 36 to increase the surface area in contact with the exhaust flow 24. To further ensure adequate cooling of the oil 12, at least one rod 72 is disposed within each of the plurality of tubes 36 to form an annulus 76 through which the oil 12 flows. Formation of the annulus 76 causes the oil 12 to flow through the plurality of tubes 36 at regions in close proximity to an inner surface 78 of the plurality of tubes 36, thereby increasing the beneficial cooling effects of the exhaust flow 24. Additionally, the rod 72 includes a machined surface that may include various features to increase turbulence of the oil flow, thereby enhancing cooling of the oil 12 while flowing within the annulus 76. Specifically, the machined surface of the rod 72 may include a knurled surface, for example.

A method of cooling oil 100 is also provided, as illustrated in FIG. 5 and with reference to FIGS. 1-4. The oil cooling arrangement 10 and the associated turbine system 14 have been previously described and specific structural components need not be described in further detail. The method of cooling oil 100 includes supplying 102 an oil to a first manifold of an oil cooling arrangement. The oil is routed through a first tube 104 from the first manifold to a second manifold, wherein the first tube is disposed in a turbine exhaust path. The oil is routed through a second tube 106 from the second manifold to the first manifold, wherein the second tube is disposed in the turbine exhaust path. The method also includes flowing an exhaust flow 108 through the turbine exhaust path and over the first tube and the second tube for cooling the oil routed therein.

Advantageously, the oil cooling arrangement 10 and the method of cooling oil 100 simplifies the heat exchanger structure with higher reliability by enhancing the cooling capability of the structure. Additionally, elimination of an on-board water source that constitutes unnecessary mass is achieved. The reduction in mass provides the opportunity to increase payload mass or reduce fuel consumption.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

1. An oil cooling arrangement comprising: a first manifold; a second manifold, wherein the first manifold and the second manifold are each configured to route an oil; a first tube having a first end proximate the first manifold and a second end proximate the second manifold, wherein the first tube is configured to receive the oil and route the oil toward the second manifold; a second tube having a third end proximate the second manifold and a fourth end proximate the first manifold, wherein the second tube is configured to route the oil from the second manifold toward the first manifold; and a turbine exhaust path configured to route an exhaust flow, wherein the first tube and the second tube are disposed along the turbine exhaust path, wherein the oil is cooled upon passage of the exhaust flow over the first tube and the second tube.
 2. The oil cooling arrangement of claim 1, further comprising a plurality of fins extending from an outer surface of each of the first tube and the second tube.
 3. The oil cooling arrangement of claim 1, further comprising a rod disposed within each of the first tube and the second tube, wherein the rod and an inner surface of the first tube and the second tube define an annulus within the first tube and the second tube for the oil to flow through.
 4. The oil cooling arrangement of claim 1, further comprising a cover member operatively coupled to the first manifold.
 5. The oil cooling arrangement of claim 4, wherein the cover member comprises an inlet region and an outlet region.
 6. The oil cooling arrangement of claim 4, further comprising a thermal control valve disposed within the cover member and proximate an oil cooling arrangement bypass, wherein the thermal control valve is in fluid communication with the inlet region and the outlet region.
 7. The oil cooling arrangement of claim 6, wherein the thermal control valve is moveable between a first position and a second position.
 8. The oil cooling arrangement of claim 7, wherein the first position comprises a fully open position and the second position comprises a fully closed position.
 9. The oil cooling arrangement of claim 8, wherein the thermal control valve is in the fully open position at a temperature less than and equal to about 250° F. (about 121° C.) and is in the fully closed position at a temperature greater than and equal to about 270° F. (about 132° C.).
 10. The oil cooling arrangement of claim 5, further comprising a pressure relief valve disposed within the cover member and configured to detect a pressure differential between the inlet region and the outlet region.
 11. The oil cooling arrangement of claim 1, further comprising: a third tube having a fifth end proximate the first manifold and a sixth end proximate the second manifold, wherein the third tube is configured to receive the oil and route the oil toward the second manifold; and a fourth tube having a seventh end proximate the second manifold and an eighth end proximate the first manifold, wherein the fourth tube is configured to route the oil from the second manifold toward the first manifold.
 12. The oil cooling arrangement of claim 11, further comprising a cover member operatively coupled to the first manifold, wherein the cover member comprises an inlet region and an outlet region.
 13. The oil cooling arrangement of claim 12, wherein the first manifold separates the oil into the first tube and the third tube for routing toward the second manifold.
 14. The oil cooling arrangement of claim 13, wherein the second manifold includes a first fluid path and a second fluid path, wherein the first fluid path fluidly couples the first tube to the second tube, and wherein the second fluid path fluidly couples the third tube to the fourth tube.
 15. A method of cooling oil comprising: supplying an oil to a first manifold of an oil cooling arrangement; routing the oil through a first tube from the first manifold to a second manifold, wherein the first tube is disposed in a turbine exhaust path; routing the oil through a second tube from the second manifold to the first manifold, wherein the second tube is disposed in the turbine exhaust path; and flowing an exhaust flow through the turbine exhaust path and over the first tube and the second tube for cooling the oil routed therein.
 16. The method of claim 15, further comprising increasing a heat transfer rate by flowing the exhaust flow over a plurality of fins operatively coupled to an outer surface of the first tube and the second tube.
 17. The method of claim 15, further comprising positioning a thermal control valve in a fully open position, wherein the thermal control valve is disposed within a cover member and proximate an oil cooling arrangement bypass, wherein the thermal control valve is in fluid communication with an inlet region and an outlet region, wherein the thermal control valve is in the open position at a temperature less than or equal to about 250° F. (about 121° C.).
 18. The method of claim 17, wherein the thermal control valve is in a fully closed position at a temperature greater than or equal to about 270° F. (about 132° C.).
 19. The method of claim 15, further comprising: routing the oil to an inlet disposed proximate the first manifold; and separating the oil into the first tube and a third tube for routing toward the second manifold.
 20. The method of claim 19, further comprising: flowing the oil from the first tube to the second tube through a first fluid path of the second manifold; flowing the oil from the third tube to the fourth tube through a second fluid path of the second manifold; and routing the oil through the second tube and the fourth tube from the second manifold toward the first manifold. 